A little under bite may not matter that much. Not sure about a over bite, that probably would create a big biting disadvantage. Considering how a dog bites bones etc. Dogs that have a long strong wide muzzle with the big jaw muscles on the side of head. Black Bull Terrier type eyes forward. Most of this types can really bite hard and get out of bad holds easier.

Not talking about a English bull terrier type muzzle etc. Lot of those freak bred dogs have bad over bites. There was a old book reprinted on the first breeder of the English Bull Terrier with old pictures. Not even the same type looking dog today.

Dogs with too big of a over all head can be at a disadvantage. Like a Boxer with arms/shoulder etc. built up to big for their weight size. Just more weight to hold up in the tiring latter rounds.

I always liked the A.P.B.T. Standard shown on the front of the old Pete Spark's Your Friend and Mine magazines. Most of these type looking dogs are found in the 45 pound to lower weights of 35 to 30 pounds.